Among percutaneously-placed catheters, for example central venous catheter, which is used for administration of high-calorie infusion or the like, is inserted into a blood vessel mainly by direct needle puncture method. Specifically, an opening is formed at the insertion site with a needle; a central venous catheter is inserted through the opening to the superior vena cava called central vein close to the heart until the distal end of the catheter reaches a desired site; and a high-calorie infusion is administered from the proximal end of the catheter placed outside the body (Patent Documents 1 and 2).    Patent Document 1: JP-A-2002-17860    Patent Document 2: JP-A-63-71259